Movable access points and repeaters for minimizing coverage and capacity constraints in a wireless communications network and a method for using the same

ABSTRACT

A system and method for improving the ability of a wireless communications network, such as a packet-switched data communications network, to provide service to mobile user terminals. The system and method employs a mobile access point, adapted for use with the packet-switched communications network comprising at least one fixed access point, to provide a mobile wireless user terminal with access to the network, and a method for using the same. The mobile access point comprises at least one transceiver, which can be mounted to a mobile vehicle and receive substantially constant power from the vehicle, and which is adapted to transmit and receive communications signals to and from the wireless user terminal, and to operate as a communications link between the wireless user terminal and the fixed access point, to provide the wireless user terminal with access to the network via the communications link. The transceiver is further adapted to provide a second communications link between the user terminal an another user terminal, or between the mobile access point and another mobile access point of the network. The mobile access point further includes technology, such as global positioning system (GPS) technology, which adapted to determine a geographic location of the mobile access point.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to movable access points andrepeaters in a wireless communications network for minimizing coverageand capacity constraints in the network. More particularly, the presentinvention relates to constantly moveable access points of a core networkof an ad-hoc wireless packet-switched data communications network, whichprovide user terminals with access to the core network and also arecapable of functioning as repeaters between user terminals to enhancethe self healing capabilities of the ad-hoc network.

[0003] 2. Description of the Related Art

[0004] Wireless communications networks, such as mobile wirelesstelephone networks, have become increasingly prevalent over the pastdecade. These wireless communications networks are commonly referred toas “cellular networks”, because the network infrastructure is arrangedto divide the service area into a plurality of regions called “cells”.

[0005] Specifically, a terrestrial cellular network or other type ofconventional specialized mobile radio (SMR) system includes a pluralityof interconnected stationary base stations that are distributedgeographically at designated locations throughout the service area. Eachstationary base station includes one or more transceivers that arecapable of transmitting and receiving electromagnetic signals, such asradio frequency (RF) communications signals, to and from user terminals,such as wireless telephones, located in its coverage area. Thecommunications signals include, for example, voice data that has beenmodulated according to a desired modulation technique and transmitted asdata packets. As can be appreciated by one skilled in the art, thetransceiver and user terminals transmit and receive the data packets inmultiplexed format, such as time-division multiple access (TDMA) format,code-division multiple access (CDMA) format, or frequency-divisionmultiple access (FDMA) format, which enables a single transceiver at thebase station to communicate simultaneously with several user terminalsin its coverage area.

[0006] Each base station is also connected to one or more gateways thatenable communication between the base station and other networks, suchas the Internet and the public switched telephone network (PSTN).Accordingly, the base stations in the network enable the user terminalsto communicate with each other, as well as with other destinations, suchas telephony devices, in the PSTN.

[0007] Because each base station is stationary and can only handle alimited amount of communications signal traffic from the user terminalsat any given time, the coverage area of a base station can varydepending on the amount of traffic that the base station is expected toexperience. For example, the coverage area of a base station can be setto several miles in diameter in sparsely populated regions, such asrural regions having light wireless traffic, and can be set to less thana mile in diameter in densely populated regions, such as majormetropolitan areas having heavy wireless traffic. The wirelesscommunications network therefore must employ many stationary basestations in heavily populated metropolitan areas in order for thenetwork to adequately service the user terminals in those regions.

[0008] The problem of providing an adequate number of base stations fora region is also exacerbated in areas where heavy commuting trafficoccurs. For example, in metropolitan areas, millions of commuters maytravel on specific stretches of highways during the morning and eveningrush hour periods. However, at all other times of the day and onweekends, these stretches of highway may receive only a modest amount oftraffic. Accordingly, it is impractical to deploy numerous base stationsin these commuting areas simply to accommodate the few hours ofincreased activity per weekday. The number of base stations that can bedeployed may also be limited due to space and zoning constraints. Hence,due to the lack of adequate base stations in these commuting areas, thenetwork may be incapable of adequately servicing its subscribers duringthese busy commuting hours of the workday.

[0009] Other variables, such as the distance between a user terminal anda base station it is trying to access, interference in the basestation's coverage area, the existence of structures such as buildingswhich block the line of sight (LOS) path between a user terminal and abase station, as well as regulatory and site restrictions, also createholes in the coverage areas which adversely affect the capacitycapabilities of the network. Users become aware of such holes becausethey either lose service or get very poor service in a particularlocation. In certain instances, in order for a user terminal to greatlyimprove its service, the user terminal may need only move a few feet,for example, from behind a building blocking the user terminal's LOSwith a base station to a position in the network that has adequatecoverage and capacity capabilities.

[0010] Attempts to improve the coverage area provided by a base stationinclude providing a rotating antenna at the fixed base station site.U.S. Pat. No. 6,222,504, incorporated herein by reference, disclosestechniques for reorienting an antenna of a fixed base station. Althoughthis solution may somewhat enhance the ability of a base station toservice its coverage area, the coverage area itself remains fixedbecause the base station remains fixed. Another solution can be to makethe base station towers mobile by making them airborne, such as onaircraft or on movable tracks. However, these solutions are difficult todeploy because of the size, cost and complexity of traditional basestation equipment.

[0011] As can be further appreciated by one skilled in the art, it isalso common for a mobile user terminal to travel between different basestation coverage areas during use, that is, during a single telephonecall. When this occurs, the base station whose coverage area the userterminal is leaving must transfer or “handoff” the user terminal to thebase station whose coverage area the user terminal is entering, so thatthe latter base station can become the base station via which the userterminal and network continue to communicate. In densely populated areashaving many base stations with small coverage areas, this handoffprocess may need to occur several times during a short period of time asthe user terminal travels between the different coverage areas. However,in regions such as high traffic commuting regions having an inadequatenumber of base stations, more user terminals are competing for access toa base station within their coverage area. Accordingly, the number oflost or dropped calls that may occur during the handoff process can beincreased due to the lack of adequate base station accessibility.

[0012] Many techniques have been developed using the circuit-switchedcellular infrastructure to minimize data packet loss during handoffwhile also minimizing overhead necessary to successfully perform thehandoff. For example, a technique known as “hard handoff” refers to abreak-before-make technique where the original connection is droppedbefore the new connection is established. On the other hand, “softhandoff” is a make-before-break technique that maintains multiplesimultaneous connections to the user terminal during handoff, and onlydrops the original connection after the new connection is established.Examples of soft handoff techniques are described in a publication byWong et al. entitled “Soft Handoffs in CDMA Mobile Systems”, IEEEPersonal Communications, December 1997, pp. 6-17, in a publication byWong et al. entitled “A Pattern Recognition System for HandoffAlgorithms”, IEEE Journal on Selected Areas in Communications, Vol. 18,No. 7, July 2000, pp. 1301-1312, and in TIA document TIA/EIA-95-Bentitled “Mobile Station-Base Station Compatibility Standard forWideband Spread Spectrum Cellular Systems”, Feb. 1, 1999, the entirecontents of each of these documents being incorporated herein byreference.

[0013] With the arrival of the Internet in recent years, some wirelesscommunications networks have moved away from the use of conventionalcellular networks and their associated circuit switched routingtechniques to improve voice communications services. Each mobile userterminal, telephony device, and any other device capable ofcommunicating with the communications network, has a unique InternetProtocol (IP) address that uniquely identifies it from all otherdevices. A communications network employing IP sends data betweendestination points in digital form in discrete packets, rather than inthe traditional circuit-committed protocols of the PSTN. Each of thedata packets includes the sender's IP address as well as the intendedreceiver's IP address.

[0014] When a wireless user terminal, for example, transmits voice datato a base station of the communications network acting as the accesspoint for the user terminal, a router associated with the base stationreads the receiver IP address in the data packet. Each router includes atable of routing information, such as IP addresses of the devices localto the router, available routes, and so on. If the router recognizesfrom the receiver IP address that the data packet is intended for atelephony device in its immediate neighborhood or domain, the routerforwards the data packet to that telephony device. However, if therouter does not recognize the IP address as belonging to such atelephony device, the router forwards the data packet to an appropriateadjacent gateway in, for example, the Internet. The router of thatgateway then reads the receiver IP address in the data packet, andeither delivers the data packet to the appropriate telephony device inits domain, or forwards the data packet to another gateway. Once arouter in a gateway recognizes the receiver IP address as belonging to atelephony device in its domain, the router in that gateway delivers thedata packet to that telephony device.

[0015] It can be also noted that the use of IP to route data packets ina communications network enables the network to handle data other thanvoice data. For example, such IP techniques can be used to expand theversatility of the network to communicate audio, video or multimediadata between user terminals. Such networks can be configured aspacket-switched data networks, as opposed to traditional circuitswitched networks. A communications network employing a packet-switchedcore network is described, for example, in U.S. patent application Ser.No. 09/897,790 entitled “Ad Hoc Peer-to-Peer Mobile Radio Access SystemInterfaced to the PSTN and Cellular Networks”, filed on Jun. 29, 2001,the entire content of which is incorporated herein by reference. Anexample of a wireless local area network (LAN) having mobility is setforth in IEEE Standard 802.11, Aug. 20, 1999, the entire content ofwhich is incorporated herein by reference.

[0016] As in traditional cellular communications networks, wireless userterminals in a wireless communications network employing IP can bemobile, and can thus periodically change their access point to thenetwork. Also, wireless user terminals can move outside their “home”network and become temporarily affiliated with a foreign network, andthus communicate via an access point on that foreign network.

[0017] Hence, as with traditional cellular communications networks,similar problems can arise in these packet-switched data networks whichservice mobile user terminals. That is, these types of networks can alsoexperience an increased occurrence of dropped or lost datacommunications for mobile user terminals, and the inability of mobileuser terminals to adequately access the network, if the number of accesspoints deployed in high traffic areas is inadequate. U.S. Pat. No.6,222,463, incorporated herein by reference, discloses a device that canbe placed in vehicles to provide information about the vehicle to fixedroadside base stations to enable the base stations to track thevehicles. However, this patent does not provide any suitable solutionfor eliminating the problems discussed above relating to holes in thecoverage areas of traditional cellular networks or packet-switched datanetworks. Accordingly, a need exists for a packet-switched data networkhaving improved coverage and capacity capabilities, and a minimal amountof holes in its coverage area.

SUMMARY OF THE INVENTION

[0018] An object of the present invention is to provide a system andmethod for improving the ability of a wireless communications network,such as a packet-switched data communications network, to provideservice to mobile user terminals.

[0019] Another object of the present invention is to provide mobileaccess points for a wireless communications network, in particular, apacket-switched data communications network, to minimize the amount ofholes in the coverage areas of the network to thus improve service tomobile user terminals accessing the network.

[0020] These and other objects of the present invention aresubstantially achieved by providing a mobile access point, adapted foruse with a packet-switched communications network comprising at leastone fixed access point, to provide a mobile wireless user terminal withaccess to the network, and a method for using the same. The mobileaccess point comprises at least one transceiver, which adapted totransmit and receive communications signals to and from the wirelessuser terminal, and to operate as a communications link between thewireless user terminal and the fixed access point, to provide thewireless user terminal with access to the network via the communicationslink, and which is housed in a structure that is adapted to mount on orin a mobile vehicle. The mobile access point further includes a powerconnection, that is adapted to couple to a substantially constant powersupply, such as the power supply of the mobile vehicle, to providesubstantially constant power to the transceiver. The transceiver isfurther adapted to provide a second communications link between the userterminal an another user terminal, or between the mobile access pointand another mobile access point of the network. The mobile access pointfurther includes technology, such as global positioning system (GPS)technology, which adapted to determine a geographic location of themobile access point.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] These and other objects, advantages and novel features of theinvention will be more readily appreciated from the following detaileddescription when read in conjunction with the accompanying drawings, inwhich:

[0022]FIG. 1 is a block diagram of an example of a wirelesscommunications network employing mobile access points for providingmobile user terminals with improved access to the network according toan embodiment of the present invention;

[0023]FIG. 2 is a block diagram illustrating an example of a wirelessmobile access point of the network shown in FIG. 1 according to anembodiment of the present invention;

[0024]FIG. 3 is a block diagram illustrating another example of awireless mobile access point of the network shown in FIG. 1 according toanother embodiment of the present invention;

[0025]FIG. 4 is a conceptual block diagram illustrating an exemplarymanner in which a mobile access point of the network shown in FIG. 1operates to provide a mobile user terminal access to the network inaccordance with an embodiment of the present invention;

[0026]FIG. 5 is a conceptual block diagram illustrating an exemplarymanner in which a mobile access point of the network shown in FIG. 1operates as a link in between mobile user terminals used in the networkshown in FIG. 1 in accordance with an embodiment of the presentinvention; and

[0027]FIG. 6 is a further conceptual block diagram illustrating anotherexemplary manner in which a mobile access points of the network shown inFIG. 1 operates as a link between mobile user terminals used in thenetwork and to provide those mobile user terminals with access to thenetwork in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028]FIG. 1 is a block diagram illustrating an example of a wirelesscommunications network 100 employing mobile access terminals accordingto an embodiment of the present invention. As shown, network 100, whichcan be referred to as a “core network”, includes a core local accessnetwork (LAN) 102 which provides the wired infrastructure for thenetwork 100. A plurality of intelligent access points (IAP) 104, 106 and108 are coupled to and communicate with the core LAN 102. As illustratedin this example, IAP 104 is directly coupled to the core LAN 102, whileIAP 106 is coupled to core LAN 102 via backhaul interfaces 110 and 112and a T1 connection, and IAP 108 is coupled to core LAN 102 via backhaulinterfaces 114 and 116 and a T1 connection. However, any suitablebackhaul technology, such as T3, fiber and microwave, can be used.

[0029] Each IAP 104, 106 and 108 is an infrastructure device containingat least one transceiver and at least one embedded processor. In thisexample, each IAP 104, 106 and 108 further includes a 10/100 Base-TEthernet connection. However, the IAPs 104, 106 and 108 can include anytype of high-speed connection suitable for coupling to the core LAN 102.An IAP 104, 106 and 108 is configured to remain in a fixed location,such as on a building rooftop or in a building ceiling, and is providedwith a permanent source of power, such as alternating current or anyother suitable power source.

[0030] As described in more detail below, an IAP 104, 106 and 108operates to provide access for subscriber devices, such as mobile userterminals 118, to wired services provided by the network 100. Each IAP104, 106 and 108 also provides a respective fixed and known position andlocation reference, relay and wireless routing for user terminals 118within its area of coverage, and the principle network managementinterface with transceivers in wireless routers and subscriber devices,such as user terminals 118. Each wired IAP 104, 106 and 108 can bereferred to generally as a “fixed node” on the network 100, while themobile user terminal 118 can be referred to as a “mobile node”. Thewired IAP 104, 106 and 108 can also function as access points to thenetwork 100 for user terminals 118 forming an ad-hoc network asdescribed, for example, in U.S. patent application Ser. No. 09/897,790entitled “Ad Hoc Peer-to-Peer Mobile Radio Access System Interfaced tothe PSTN and Cellular Networks”, filed on Jun. 29, 2001, and as in U.S.Pat. No. 5,943,322 to Mayor, the entire contents of each beingincorporated by reference herein.

[0031] The network 100 further may include a media server 120 fordelivering types of media such as video and multimedia data to the coreLAN 102, and a domain name server (DNS) 122 for translating Internetdomain names into Internet Protocol (IP) addresses in a manner as knownin the art. The network 100 may also include a PSTN gateway 124 whichprovides data access between the network 100 and the PSTN 126, and an IPgateway router 128 which provides data access between the network 100and the Internet 130.

[0032] Further details of the network 100 and its operation will now bedescribed. For purposes of this discussion, the terms “IAP” and “node”or “fixed node” will be used interchangeably, as well as the terms “userterminal” and “mobile node”. The wired IAPs 104, 106 and 108 on the coreLAN 102 are all fully connected to a single virtual segment. As can beappreciated by one skilled in the art, all IAPs 104, 106 and 108 (fixednodes) on the virtual segment are directly accessible from any othernode at the logical link layer. IP routing is not used to reach anyother node on the virtual segment. The IP subnet for this virtualsegment is large enough to encompass all of the IAPs 104, 106 and 108,and all mobile nodes 118 in a single broadcast domain. The virtualsegment may include media access control layer (MAC-layer) bridges andswitches (not shown) between the IAPs 104, 106 and 108, as needed, tofilter unicast frames from using bandwidth on non-required links.

[0033] The wired IAPs 104, 106 and 108 will, by definition, have twonetwork interfaces, one of which is connected to the network via awire-line link, and the other being a wireless transceiver. Both ofthese interfaces will have IP addresses from the core network's IPsubnet. An IAP 104, 106 and 108 must then retain an IP routing tableindicating that the IP of the wireless transceiver interface isreachable on that interface, while all other IP addresses on that subnetare reachable directly on the wired interface. IP's outside the corenetwork's subnet are reachable via the core network's directlyaccessible IP router gateway 128.

[0034] In addition to having fixed IAPs 104, 106 and 108, the networkcan employ mobile IAPs 132. Each mobile IAP 132 is similar to a fixedIAP 104, 106 or 106 in that it operates to provide access for subscriberdevices, such as mobile user terminals 118, to wired services providedby the network 100. As shown in FIG. 2, IAP 132 includes at least onetransceiver 134 and at least one processor 136. The transceiver 134 cantransmit and receive data packets over any frequency band, for example,over the 2 ISM band. However, the frequency and modulation scheme usedby the transceiver 134 do not impact the implementation of the mobileIAP 132.

[0035] The mobile IAP 132 can be small so as to be mounted on theinterior or exterior of a vehicle 146 (see FIG. 4), such as anautomobile, truck, bus, train, taxi, police car, fire engine, or anyother suitable movable vehicle. For example, the housing of the IAP 132can be a rectangular box having dimensions of approximately 4 inches by6 inches by 1 inch. By incorporating such a device in a new automobileup to 15 million could be deployed annually. The mobile IAP 132 furtherincludes an antenna 138 that can be internally or externally mounted tothe vehicle 146. This antenna 138 can have a gain higher than that of anantenna typically employed in a mobile user terminal 118.

[0036] The mobile IAP 132 further has a connection 140 to asubstantially constant external power supply, such as the 12V DC powersupply of the vehicle 138. The mobile IAP 132 can further includepositioning functionality 141, such as global positioning system (GPS)functionality, differential navigation functionality, or otherpositioning functionality such as various triangulation techniques ascan be appreciated by one skilled in the art, which enables the IAP 132to know its actual geographic location and to provide this informationto the network 100 and to the user terminals 118 using or attempting touse the mobile IAP 132 as their access point to the network 100.

[0037]FIG. 3 illustrates a higher capacity version of a mobile IAP 132-1which includes multiple transceivers 134-1 and 134-2 each coupled to arespective antenna 138-1 and 138-2, a single processor 136-1, such as asingle board control computer, and a connection 140-1 for connecting toan external power supply, such as the 12 V DC power supply of thevehicle 146. The mobile IAP 132-1 also includes the positioningfunctionality 141-1 similar to positioning functionality 141 discussedabove. The housing of this version of a mobile IAP 132-1 can havedimensions approximately 12 inches by 6 inches by 1 inch, and can bemounted in a larger vehicle such as a city bus or refuse wagon. Thishigher capacity mobile IAP 132-1 also includes all of the functionalitypresent in mobile IAP 132 as discussed above.

[0038] Referring back to FIG. 1, it is noted that each mobile IAP 132(or 132-1) must be capable of communicating with a fixed IAP via awireless backhaul, such as a microwave backhaul 144, as can beappreciated by one skilled in the art. In order to minimize the numberof fixed IAPs 104, 106 and 108 and mobile IAPs 132 employed in thenetwork 100 while also maximizing the coverage and capacity of thenetwork 100, the fixed IAPs 104, 106 and 108, as well as the mobile IAPs132, can utilize a self forming self healing radio access technology asdescribed in U.S. patent application Ser. No. 09/897,790 and in U.S.Pat. No. 5,943,322, both referenced above. In addition, all of the fixedIAPs 104, 106 and 108, as well as the mobile IAPs 132 (and 132-1) arecapable of performing proxying operations and handoff operations asdescribed in copending U.S. patent application of Charles R. Barker, Jr.et al. entitled “A System and Method for Providing an Addressing andProxy Scheme for Facilitating Mobility of Wireless Nodes Between WiredAccess Points on a Core Network of a Communications Network”, (AttorneyDocket No. 41743), and in a copending U.S. patent application of RobinU. Roberts et al. entitled “A System and Method for Performing SoftHandoff in a Wireless Data Network”, (Attorney Docket No. 41744), bothof said patent applications being filed even date herewith and thecontents of each being incorporated herein by reference. Thetransceivers 134 (and 134-1 and 134-2) of each mobile IAP 132 (and132-1) also are capable of performing routing operations as described,for example, in U.S. patent application Ser. No. 09/897,790 and in U.S.Pat. No. 5,943,322, both reference above and incorporated herein byreference.

[0039] Hence, as shown in FIGS. 1 and 4, the mobile IAP 132 can providea user terminal 118 with access to the network 100 via a fixed IAP, suchas fixed IAP 108. It is noted that the conceptual diagram shown in FIG.4 indicates that the network 100 can also include a network operationscenter (NOC) 148, a gate keeper (GK) 150, and anauthentication/authorization/accounting (AAA) center 152, the purposesof which can be appreciated by one skilled in the art. Furthermore, asshown in FIG. 5, a mobile IAP 132 can operate as a router to enableintercommunication between mobile terminals 118 which can be hand-heldor present in other vehicles 154 and 156. In addition, as shown in FIG.6, the mobile IAPs 132 can use each other in conjunction with anotheruser terminal 118 in the ad-hoc network, such as a user terminal 118present in a vehicle 154, to connect to a fixed IAP, such as IAP 108.The mobile IAPs 132 can also establish communications links between eachother in the ad-hoc network.

[0040] Accordingly, the functionality of the mobile IAPs 132 and 132-1as described above provide a sufficiently mobile infrastructure for thenetwork 100, which minimizes the number of the holes in coverage as wellas the amount of time that such holes in coverage exist at any locationin the network 100. A user terminal 118 who remains stationary may seethe signal quality ebb and flow as this infrastructure moved, but wouldon average observe acceptable signal levels. Also, as can be appreciatedby one skilled in the art, modem existing protocols (such as TCP/IP) canovercome the small periods of time when coverage became unacceptablewithout breaking the connection or loosing data packets. In addition,due to the self-healing features of the ad-hoc network, the coverage andcapacity provided by the mobile IAPs 132 and 132-1 will generally begreatest at the locations with the greatest number of user terminals118.

[0041] Another advantage provided the mobile IAPs 132 and 132-1 is thatthey can aggregate traffic to the core LAN 102 (see FIG. 1) byconcatenating many smaller data packets into larger ones. This techniquemakes the overall network 100 more efficient. Likewise, the core LAN 102can aggregate data packets to the mobile IAP 132 or 132-1. The mobileIAP 132 (or 132-1) and core LAN 102 may use the same modulation schemeand frequency as the access network, but are not required to do so if itis determined that a different scheme may be optimal.

[0042] Furthermore, if the mobile IAPs 132 or 132-1 are moving at arelatively constant rate and relatively slowly in relation to the mobileuser terminals 118, they will have the added benefit of minimizing theDoppler shift issues that plague mobile radio. That is, as can beappreciated by one skilled in the art, Doppler shift issues are moresignificant for a user terminal 118 travelling at 70 mph with respect toa stationary IAP (e.g., IAP 104, 106 or 108) in comparison to thoseassociated with a user terminal 118 travelling at 70 mph and a mobileIAP 132 or 132-1 which is moving at 35 mph relative to a stationary IAP104, 106 or 108 and the core LAN 102, because the relative movementbetween the user terminal 118 and mobile IAP 132 or 132-1 is only 35mph, and the relative movement between the mobile IAP 132 or 132-1 andthe stationary IAP 104, 106 and 108 and core LAN 102 is only 35 mph.Hence, the overall Doppler shift effect is reduced.

[0043] Although only a few exemplary embodiments of the presentinvention have been described in detail above, those skilled in the artwill readily appreciate that many modifications are possible in theexemplary embodiments without materially departing from the novelteachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention as defined in the following claims.

What is claimed is:
 1. A mobile access point, adapted for use with apacket-switched communications network comprising at least one fixedaccess point, to provide a mobile wireless user terminal with access tothe network, said mobile access point comprising: at least onetransceiver, adapted to transmit and receive communications signals toand from said wireless user terminal, and to operate as a communicationslink between said wireless user terminal and said fixed access point, toprovide said wireless user terminal with access to said network via saidcommunications link; and a structure, adapted to house said at least onetransceiver, and being adapted to mount on or in a mobile vehicle.
 2. Amobile access point as claimed in claim 1, further comprising: a powerconnection, adapted to couple to a substantially constant power supply,to provide substantially constant power to said transceiver.
 3. A mobileaccess point as claimed in claim 2, wherein: said power connection isadapted to coupled to said substantially constant power supply of saidvehicle.
 4. A mobile access point as claimed in claim 1, wherein: saidtransceiver is further adapted to provide a second communications linkbetween said user terminal an another user terminal.
 5. A mobile accesspoint as claimed in claim 1, wherein: said transceiver is furtheradapted to provide a second communications link with another mobileaccess point adapted for use with said network.
 6. A mobile access pointas claimed in claim 1, further comprising: a location determiner,adapted to determine a geographic location of said mobile access point.7. A mobile access point as claimed in claim 6, wherein: said locationdeterminer includes a global positioning system (GPS) receiver.
 8. Amethod for providing a mobile access point in a packet-switchedcommunications network comprising at least one fixed access point, toprovide a mobile wireless user terminal with access to the network, saidmethod comprising: coupling a mobile access point to a mobile vehicle;and transmitting and receiving communications signals between saidmobile access terminal and said wireless user terminal; and establishinga communications link between said mobile access terminal and said fixedaccess point, such that said communications link provides said wirelessuser terminal access to said network via said fixed access point.
 9. Amethod as claimed in claim 8, further comprising: providingsubstantially constant power to said mobile access point.
 10. A methodas claimed in claim 9, wherein: said providing provides saidsubstantially constant power supply from a power supply of said vehicle.11. A method as claimed in claim 8, further comprising: using saidmobile access point to provide a second communications link between saiduser terminal an another user terminal.
 12. A method as claimed in claim8, further comprising: providing a second communications link betweensaid mobile access point and another mobile access point adapted for usewith said network.
 13. A method as claimed in claim 1, furthercomprising: determining a geographic location of said mobile accesspoint.
 14. A method as claimed in claim 13, wherein: said locationdetermining includes using global positioning system (GPS) technology todetermine said geographic location of said mobile access point.